Hydraulic remote control system



March 27, 1945- E. DOUGHERTY HYDRAULIC REMOTE CONTROL SYSTEM Filed April 29, 1945 2 sheets-sheet 1 n INVENTOR. LEMUEL E. UCv'/EHTY Lfd/466? HTTORNEY l March 27, 194s;

L. E. DOUGVHERTY HYDRAULIC REMOTE CONTROL SYSTEM 24 sheets-sheet 2 Filed April 29, 1943 IN V EN TOR.

T .an n N E n M. w U r o A w.

uw u Patented Mar. 27, 1945 HYDRAULIC REMOTE CONTROL SYSTEM Lemuel E. Dougherty, Fairhope, Application April 29, 1943, Serial No. 484,998

(Cl. (io-54.5)

9 Claims.

This inventionmay be considered a further improvement or developmentof my inventionsregarding hydraulic remote controls as shown in my applications-for U. S. Patent Serial No. 449,-

942, filed July 6, 1942, and Serial No. 459,176, filed September 21, 1942. 1

The primary object in both of the above mentioned inventions is to provide an automatic locklng means at the receiver end of the system to.

hold the receiver or operated end of the system from any movement due to the exertion of external vforces thereon or from any expansion, contraction or leakage of fluid from the system.

While the locking of the receiver or operated end of the system when the transmitter handle was not being operated served to eliminate errors in position of the receiver element during this tained in the connecting duct between the transmitter and the receiver, is free to expand and 1 contract during `normal times, that is, in the intervals when the transmitter handle is not being operated, without, however, destroying synchronism which exists at all times between the transmitter element andthe receiver element.

For this purpose I utilize a separate expansion and compression system with which the connecting duct is normally in engagement when the transmitter handle is not being actuated so that all expansion and contraction of the fluid in the connecting duct will be taken up by this expansion chamber at the same time both the transmitter and the receiver elements are disconnected from the connecting duct. Means are then provided whereby upon actuation of the transmitter handle in one `direction or the other, the connecting duct is automatically disconnected from the expansion chamber and connected to the transmitter and to the receiver so that all movements of the transmitter will be instantaneously transmitted to the receiver.

It is a further object of this invention to provide a plurality of transmission systems, each system comprising a transmitter, a receiver and a duct connecting said transmitter and receiver, together with a common .expansion chamber with which all of said ducts are normally connected. Actuation of the transmitter of any system disconnects the respective duct from the common expansion chamber and connects. it to the transmitter and receiver of that system.

Further objects and advantages of this inventailed description thereof:

In the accompanying drawings,

Fig. 1 is across sectional view of the transmitter assemblage. f

Fig. 2 is a top sectional view of the transmitter 4assemblage taken on the line 2-2 of Fig. 1.

Fig. 3 is a cross sectional view` of a part of the transmitter assemblage snowing a modified form of valve assemblage.

4 is 'a cross sectional View of a part of the transmitter assemblage showing a modiiied form of valve assemblage.

Fig. 5 is a 4cross sectional view of the receiver assemblage. with locking` valve attached.

Fig. 6is a diagrammatic illustration of a plurality of independent control systems connected to a single compressorunit. y

Referring to Fig. 1, the transmitter assemblage is comprised of three main parts: the transmitter cylinder and piston assembly; a compressor cylinder and piston assembly; and a valve assembly which controls the connection of either of these cylinders to the receiver assemblage..

The transmitter cylinder and piston assembly is very similar to that shown in aforementioned patent applications and consists primarily of the frame I0,"cylinder II with the piston I2 slidable therein. The spring 26 is held under compression upon the rod 24. being seated at one end upon the disc 2l andat the other end in the collar 23. This collar is pivotally mounted in the frame at the points 'I5-l5 as shown in Fig. 2. The rod 24 is pivotally connected at 2l to the operating lever I8 which is pivoted in Irame I0 at 22 and connected to the piston by means of the rod I8. This linkage between the spring and the piston provides a substantially constant pressure force upon the fluid in the cylinder Il below the piston. That part of the cylinder between the upper and lower heads of the piston, which are equipped with the seals 3|l and I6, respectively. is Iilled with uid under very low pressure by gravity or otherwise from a supply tank Il through passage 16 and the port I1. The proper quantity of nuid in the system is maintained by means of` the synchronizing valve I5 in the head of the piston. The xed rod I4 extends transversely across the cylinder and through the slot I3 in the piston. Movement of the piston to the upward extent of its stroke causes this valve to be opened by striking against the rod I4, thus connecting the supply tank or reservoir 1l to the lower or presthe piston is concerned, so that the fluid in the compressor cylinder 33 is maintained at a substantially constant pressure substantially equal to the pressure on the iluid in the transmitter cylinder ll. For this purpose a spring 45 is held under compression upon the rod 43, being seated at one end upon the disc 48 and at the other end in the collar 42. This collar is pivotally mountedin the frame |`at the points 14-14 as shown in Fig. 2. The rod 43 is pivotally connected at 4| to the lever 39 which is pivoted in frame I0 at 50 and connected to the piston 35 by means of the rod 35 at point 38, said rod being con nected to the piston at pivot 31.

The transmitter valve assembly consists of valves 63 and 60 which are attached to the diaphragms 50 and 5|, respectively. The spring 65, under compression, is seated against the diaphragm 50, tending to close valve 63. The spring 10, under compression, is seated against diaphragm 5 I, tending to open valve y|50. Fluid pressure from the tran'smittercylinder enters through the passage 48 to the chambers below the diaphragms so that the force of the fluid pressure against the diaphragms is in opposite relation to the force of the springs acting thereon. Under the normal uid pressure maintained in thetransmitter cylinder this force from the iiuid pressure against the diaphragm '50 is slightly greater than the opposite force of the spring 35 so that the valve 53 is normally open. The force of the spring is slightly greater than the force of the normaliiuid pressure against diaphragm 5| so that the valve 50 is normally held open. The ball check valve 51 is normally held closed by the spring 58 but will open upon a predetermined increase in pressure from the transmitter cylinder. The ball check valve 55 is normally held closed by the spring 54 but will open upon a predetermined decrease in uid pressure from the transmitter. Fluid connection from the transmitter assemblage to the receiver assemblage is by means of the connecting tube or duct 12;

With the system at rest, that is, when no motion is being transmitted, fluid connection from the receiver is through the connecting tube 12, the passage 56, the open valve 60, the passage 62, the open valve 63 and the passage 64 to the compressor cylinder 33. As described in my hereinbefore mentioned co-pending applications, and as will be again described hereinafter, the receiver is normally held against movement by the locking valve assemblage shown in Fig. 5. Therefore, it is seen that any change in volume of iluid in the connecting tube 12 will cause movement of the compressor piston 35 only, and will not affect the position of the transmitter. When it isdesired to transmit movement between the transmitter and receiver, force exerted upon the transmitter operating leverand consequent increase or decrease of fluid pressure in the transmitter cylinder will cause one of the valves to close, thus disconnecting the compressor cylinder 33 from the connecting tube 12, and fluid is transferred from the transmitter to the receiver by passage through the check valves 51 or 55. Force exerted downwardly on the transmitter piston will increase the fluid pressure in the cylinder Il. When this pressure has increased suiliciently to open check valve 51 and allow now to the receiver, this increased pressure upon diaphragm 5| will have closed the valve 50. Force exerted on the transmitter operating lever so as to move the transmitter piston upwardly, thus decreasing the pressure in the cylinder, causes valve 53 to close before the check valve 55 has opened. It is thus seen that when it is desired to transmit motion between the transmitter and receiver, one of the transmitter valves will close and disconnect the compressor from the system, but as soon as such movement is stopped, both of these valves will be open and the compressor connected to the system. Any change in volume of iiuid in the connecting line taking-place when the transmitter is not being operated, will, therefore, be

Vcompensated for by movement of the compressor piston, and no movement will take place in the transmitter because the latter is disconnected -from duct 12 by the valves 55 and 51.

In Fig. 5 there is shown a receiver and locking valve assemblage of the type described in my said co-pending patent applications, which may be used in this system. I here illustrate the iiuid locking means of my application, Serial No. 449.942, but itwill be apparent to those skilled in the art that the locking means of my later filed application, Serial No. 459,176, can also be used in the system.

In this lever assemblage a spring |45 is held under compression upon the rod |45 being seated at one end upon the disc |41 and at the other end in the collar |42. This collar is pivotally mounted in the frame |30 on pivots (not shown) similar to pivots 14 and 15. The rod |43 is pivotally connected at |33 to the lever |33 which is pivoted in the frame |30 at |40 and connected to the piston |33 by means of rod |35 which is pivoted at |31 to lever |38, and at |34 to the piston |33. This linkage is similar to that employed in the transmitter, the spring thus normally maintaining iluid pressure in the receiver cylinder substantially constant and equal to the iiuid pressure maintained in the transmitter and compressor cylinders.

Normally when the transmitter handle is not being operated the pressure of spring 45 upon piston 35 places under pressure the fluid which com municatesv with expansion reservoir 33 and extends from this reservoir by way of passage 54, open valve 53, passage 52, open valve 50, passage f 55 and connecting'duct 12 to the receiver assemblage. The receiver piston |33, however, is normally cut oil from the duct 12 by reason of the fact that said duct communicates with the receiver cylinder by way of valves |54 and |58,

.which are normally closed. The valve |55 is normally closed because the force of the transmitter fluid pressure upon diaphragm |54 is slightly greater than the oppositely acting force of. the compression spring |56. The valve |55 is normally closed because the force of the compression spring |51 is greater than the force of the transmitter uid pressure upon the diaphragm |55. Under normal uid pressure in the system both ol.' these valves are closed, thus efi'ectively disconnecting the receiver piston from duct 12 and locking the receiver against movement. fluid pressure from the transmitter will cause one of these valves to open, thus connecting the transmitter and receiver cylinders and allowing flow of iiuid and transmittal of motion between them. Thus, movement of the transmitter handle in a direction to increase the pressure in duct 12 increases the pressure upon diaphragm |55 to open valve |58 and establish communication with the receiver piston. Movement of the transmitter handle in the opposite direction to decrease the pressure in duct 12 enables spring |56 to overcome the pressure on the diaphragm and A predetermined increase or,decrease in.

. in the transmitter fluid pressure.

v open valve |54, and thus establish communication between the receiver piston and the duct-12.

yThe operation of the device as thus far described is therefore as follows:

Normally the connecting duct 12 is dlscon- 5 nected from both the transmitter piston I2 and the receiver piston |33, but is connected to the expansion chamber 33 acting upon the piston 35. Thus, two conditions normally prevail. First, the transmitter and the receiver are locked in which ever positions they have lbeen set. Second, any expansion or contraction in the main body of fluid in the system which is'in the connecting duct will have no effect -upon either the transmitter or the receiver, and thus will not intron l5 duce an error in the positioning of either of these elements, but such expansion and contraction will take place entirely in the expansion chamber where it will act upon the piston 35. As soon, however7 as the transmitter lever is actuated in 20 one direction or the other, the expansion chamber is disconnected from the connecting duct 'l2 (by closing valve 63 or valve 60), and the said connecting duct is connected to the transmitter (through valve or valve 5l), and to the re- 23 celver (through valve |54 or |58). All this is performed automatically merely at the actuation* of the transmitter handle which serves to increase or decrease the pressure which normally is maintained in the connecting duct 'i2 by the spring d5 30 acting upon piston 35.

Referring to Fig. 3 this transmitter valve assemblage is very similar to that in Fig. l already described, insofar as the valves are concerned.' In this modified form of construction l use fluid 3 pressure from the transmitter cylinder through passages @l and 83 on one side of diaphragms do and tt, and uid pressure from the com presser cylinder through passages i793 and t5 upon the other side of these diaphragms'. As these fluid pressures from the transmitter and the compressor are substantially equal and balance each other, it is only necessary to provide springs oi sumcient force to assure that the valves are 45 held open when the system "is at rest. The

spring at normally holds valve 92 open but an increase of fluid pressure from the transmitter cylinder will cause this valve to close. The spring' ill normally holds valve 9i open but a decrease in 5o duid pressure from the transmitter will cause this valve to close. With valves 92 and 9i open, and valves lllt and it@ (corresponding to valves El and lit) closed, the connecting duct 'l2 is connected to the reservoir 33 by Way of passages lill, 55 Sid, valve tl, valve t2 and passage When either valve t2 or valve tl closes due to increase or decrease of pressure caused by operation olf the transmitter handle, then the expansion chamloer iid is out off from duct l2, and the trans-,- @o

mitter chamber Il is connected to said duct .by Way of passages iii, til and l 12, and valve |03 or itt.

One advantage of this form of construction is that it is unnecessary to accurately balance the force of the springs against thev fluid pressure force on the dlaphragms as done in the construction shown in Fig. 1. It is only necessary to provide springs which will normally hold the valves open and allow them to close upon small changes Another vadvantage of this form of construction is that in case of a lack of a proper fluid pressure from the compressor, which might occur due to a leakage of iiuid or other cause, the valves will autopassage lll and closing the passage |23. l

' advantage this form of valve construction has is Anection tubes itl, E83, itil and itil.

matically close and disconnect the compressor from the system.

Referring to Fig. 4, inthis form of construe-v tion a piston type sliding valve is used rather than the poppet valves and diaphragms as heretofore described. The sliding piston I |8 normally closes the passage between the transmitter "cylinder Iland the connecting duct 12 to the receiver. 4A port is provided which normally allows passage ofvuid through the passages |23, |24 and |25 to thecompressor or expansion cylinder 33. The passage |24 provides fluid pressure from the compressor cylinder to the chamber l2 l,

thus acting against one end of the piston |58. The passage ||2 provides iiuid pressure from the transmitter cylinder to the chamber H3, acting upon the opposite end of the piston. The springs H5 .and E20 are pre-loaded and seatupon the washers MT and H9 which are slldable in the chambers H3 and i2l. These chambers, being larger in diameter than the piston, provide a shoulder upon which these Washers are seated. Thus there is normally no load from the springs upon the piston H8, but as soon as this piston starts to move it picks up the load of one of the springs. A predetermined increase in uid pressure from the transmitter cylinder, acting against the end of the piston H8 will cause it to move against the force of the spring l20 until its port allows iiow of fluid through the passage l l l, thus connecting the transmitter to the receiver. fore this passage is open, the piston will have moved sumciently to close the passage |23 and thus disconnect the Vcompressor cylinder from the system. A. decrease in uid pressure from the transmitter cylinder will cause the lpiston to move in the opposite direction, thus again opening the One that it is slightly simpler and less expenive to manufacture. Another advantage is that the passage to the compressor is positively closed before the passage to the transmitter is opened.

Although l have here illustrated a compressor constructed as an integral part of the transmitter assemblage, it is of course apparent that it need not be so constructed, but may be made as a separate unit and connected to the valve in the transmitter assembly by means of `a connecting tube. By following such practice, a single compresser unit may be used with a plurality of transmitter units. The volume of the compressor unit must, oi course, be sucient to accommodate the change ifi/volume of the iiuid in the connecting tubes between all of the transmitter and receiver assemblages.

lin Fig. 6 is diagrammatically illustrated such an installation of a plurality of hydraulic control systems connected to a single compressor unit. The transmitter assemblages lilf'i'a, libia, llia and Hita are connected to the receiver assemblages ltib, llilb, lb, and lllb by the respective conable ror use in aircraft or other installations where a number of control systems are used.

In accordance with the provisions of the patent statutes, I have herein described the principle and operation ci my invention, together with the A comapparatus which I now consider to represent the best embodiment thereof, but I desire to have it understood that the apparatus shown is onLv illustrative and that the invention can be-carried out by other equivalent means. Also, while it is designed to use the various features and elements in the combination and relations described, some of these may be altered and others omitted Without interfering with the more general results outlined, and the invention extends to such use.

Having described my invention what I desire and claim to secure by Letters Patent is:

1. In a iiuid transmission system comprising a transmitter, a receiver, and a duct adapted to connect the transmitter and the receiver, an expansion chamber, means for normally connecting said duct to said chamber and disconnecting said duct from said transmitter and said receiver, and

'means responsive to the actuation of said trans'- mitter for disconnecting said duct from said chamber and connecting said duct to said transmitter and said receiver.

2. In a uid transmission system comprising a transmitter, a receiver, and a duct adapted to connect the transmitter and the receiver, an eX- pension chamber,means for normally connecting said duct to said chamber and disconnecting said duct from said transmitter and said receiver, and means responsive to the actuation of said transmitter for disconnecting said duct from said chamber and connecting said duct to said transmitter and said receiver, said last named means including valve mechanisms at the transmitter and at the receiver, and means responsive to the actuation of said transmitter for actuating said r.

mechanisms.

3. In a iiuid transmission system comprising a transmitter, a receiver, and a duct adapted to connect the transmitter and the receiver, an expansion chamber, means for normally connecting said duct to said chamber and disconnecting said duct from said transmitter and said receiver, and means responsive to the actuation of said transmitter for disconnecting said duct from said chamber and connecting said duct to said transmitter and said receiver, said last namedgmeans including a set of oppositely Aacting valve mechanisms at the transmitter and a second set of oppositely acting valve mechanisms at the receiver, and means responsive to the actuation of said transmitter in one direction for actuating certain of said mechanisms at the transmitter and at the receiver, and means responsive to the actuation of said transmitter inthe other direction for actuating the other of said mechanisms at the transmitter and at the receiver.

4. In a uid transmission system comprising a transmitter, a receiver, and a duct adapted to connect the transmitter and the receiver, an expansion chamber, means for normally connecting said duct to said chamber and disconnecting said duct from said transmitter and said receiver, and means responsive to the actuation of said transmitter for disconnecting said duct from said chamber and connecting said duct to said transmitter and said receiver, said last named means including a set of oppostelyk acting valve mechanisms at the transmitter and a second set of oppositely acting valve mechanisms at the receiver, and means responsive to the actuation of said transmitter to increase the fluid pressure in the system for actuating certain of said mechanisms at the transmitter and at the receiver, and means responsive to the actuation of said transmitter to decrease the iiuid pressure in the system for actuating the other of said mechanisms at the transmitter and at the receiver.

5. In e. control mechanism, a plurality oi' nuid transmission systems, each system comprising a transmitter, a receiver and a duct adapted to connect the transmitter and the receiver, -a single expansion chamberI means for normally connecting each oi said ducts to said chamber and normally disconnecting said ducts from the transmitter and the receiver, and means responsive -to the actuation of each of said transmitters for disconnecting the respective duct from said chamber and'connecting said duct to the respective transmitter and receiver.

6. In a control mechanism, a plurality of iiuid transmission systems, each system comprising a transmitter, a receiver and a duct adapted to connect the transmitter and the receiver, a singie expansion chamber, means for normally connecting each of said ducts to said chamber and normally disconnecting said ducts from the transmitter and the receiver, and means responsive to the actuation of each of `said transmitters for disconnecting the respective duct from said chamber and connecting said duct to ythe respective transmitter and receiver only while said transmitter is being actuated.

'7. In a control mechanism, a plurality of iiuid transmission systems, each system comprising a transmitter, a receiver and a duct adapted to connect the transmitter and the receiver, a common reservoir for maintaining all of said systems lled with uid, a single expansion chamber, means for normaily connecting each oi said ducts to said chamber and normally disconnecting said ducts from the transmitter and the receiver, and means responsive to the actuation cf each of said transmitters for disconnecting the respective duct from said chamber and connecting said duct to the respective transmitter and receiver.

8. In a uid transmission system comprising a i transmitter, a receiver and a duct adapted to connect the transmitter and the receiver, a reservoir for maintaining said system lled with fluid, means for maintaining the iiuid in said system under pressure, an expansion chamber, means for maintaining said chamber under pressure substantially equal to the pressure of the uid in said system, means for normally connecting said duct to said chamber and disconnecting said duct from said transmitter and sm'd receiver, and means responsive to the actuation of said transmitter and eiiective as long as said transmitter is being actuated for disconnecting said duct from said chamber and connecting said duct to said transmitter and said receiver.

9. In a duid transmission system comprising a transmitter, a receiver and a duct adapted to connect the transmitter and the receiver, a reservoir for maintaining said system filled with uid, means for maintaining the uid in said system under pressure, an expansion chamber, means for maintaining said chamber under pressure substantially equal to the pressure of the iluid in said system, means for normally connecting said duct to said chamber and disconnecting said duct from said transmitter and said receiver, and means responsive to actuation of said transmitter for disconnecting said duct from said chamber and connecting said duct to said transmitter and said receiver.

. LEMUEL E. DOUGHERTYq 

